1. Field of the Invention
The present invention relates to a gas turbine combustor and more particularly to a structure of a gas turbine combustor intending to improve the reliability and cooling property of a transition piece for leading combustion gas generated in a combustion chamber of the gas turbine combustor to the turbine blades.
2. Description of Related Art
The transition piece composing the gas turbine combustor is a flow path for leading high-temperature and high-pressure combustion gas generated by an oxidation reaction of fuel and air in the combustion chamber of the gas turbine combustor to the turbine blades.
The transition piece of the gas turbine combustor is a duct having an entrance portion in a circular shape on the side of the combustion chamber and an exit portion in a fan shape on the side of the turbine blades and therein, high-temperature combustion gas at 1300° C. or higher flows at high speed, so that it is necessary to install some cooling facility to reduce the temperature of the member composing the transition piece to the allowable temperature or lower.
As one of the means for cooling the transition piece of the gas turbine combustor, as disclosed in Japanese Patent Laid-open No. 2001-289061, impingement cooling for cooling the transition piece by covering the whole surface of the transition piece of the gas turbine combustor with a transition piece flow sleeve and permitting an air current injected from many air holes formed in the transition piece flow sleeve to collide with the transition piece may be cited.
Further, as another one of the means for cooling the transition piece of the gas turbine combustor, as disclosed in Japanese Patent publication No. Hei 7 (1995)-52014, there is a method for cooling the end portion of the transition piece of the gas turbine combustor by covering the transition piece of the gas turbine combustor with the transition piece flow sleeve, executing the impingement cooling for the downstream side of the transition piece and convection cooling for the upstream side of the transition piece through convection cooling holes, and permitting cooling air to flow to the end of the transition piece flow sleeve on the turbine side.